The effect of marathon running on memory

We often hear that among its myriad benefits, exercise is good for the brain. Running is considered particularly good for maintaining brain health. But in the short-term, how does marathon running effect the memory of runners immediately after the marathon?

We tested the idea that real-world situations, such as the highly strenuous exercise involved in marathon running, that impose extreme physical demands on an individual may result in neurohormonal changes that alter the functioning of memory. Marathon runners were given implicit and explicit memory tasks before or immediately after they completed a marathon. Runners tested immediately upon completing the marathon showed impairment in the explicit memory task but enhancement in the implicit memory task. This postmarathon impairment in explicit memory is similar to that seen with amnesic patients with organic brain damage. However, no previous studies have shown a simultaneous enhancement in the implicit memory task, as shown by the marathon runners in the present study. This study indicates that human memory functioning can be dynamically altered by such activities as marathon running, in which hundreds of thousands of healthy normal individuals routinely partake.

In a way, the results of this study are really not all that surprising, but it is still interesting to investigate exactly what happens to runners just after they cross the finish line. I remember during the last few miles of a 25 mile run being on the verge of delirium. Running a marathon is exhausting physically and mentally, so it should come as no surprise that the brains of people who just crossed the finish line are not as sharp as before the marathon, at least when it comes to memory. This doesn’t mean running marathons is bad for the brain though, since this is almost certainly a short-term effect, probably due to low blood sugar levels.

It is the long-term effects of exercise that are important, not just the short-term.